I was thinking of making something similar to this to remove bearings from spinners that didn't work out. I was going to use the same process to remove as I use to insert -- rubber mallet. This solution with the bolt is great, and so much easier!
For my implementation, I used a 5/16th x 1 1/2" hex head bolt from Home Depot and then whipped up a couple of knobs in Fusion 360 to hold the nut and go over the head of the bolt. Works perfectly!
[12/31/16] - UPDATE: For some reason, the STL files won't upload, I think it is on the Thingiverse side, since I've tried multiple browsers / networks / PCs. So, here are drop box links to the bolt and nut holders: